Activated carbon filters of the above-described type are generally known. As a rule, they have an activated carbon packet contained in a housing made of plastic. The housing is connected, through the use of connection pieces or lines, with the fuel tank, with the intake pipe of an internal-combustion engine, as well as with the atmosphere.
A similarly constructed adsorption system is known from U.S. Pat. No. 4,058,380. In this patent, the inside volume of the housing which accommodates the absorbing material is divided into two areas via a partition.
Furthermore, from German Patent document DE-OS 41 24 653, an activated carbon filter is known which consists of an oval housing having a partition arranged therein. An activated carbon packet arranged in the oval housing is prestressed by pressure springs in order to prevent any shaking-up of the activated carbon and, therefore, any possible disturbance.
In the case of the known activated carbon filters, an interior housing consisting of plastic is surrounded by a fuel and vapor impermeable outer housing. This known filter is expensive because the outer housing cannot accommodate the required connection pieces and thus an additional cover must be used. In addition, the outer housing must be placed over the inner housing in a sealing manner so that the inner housing, which is fuel and vapor permeable, cannot emit any harmful gases into the environment.
There is therefore needed an activated carbon filter which can be manufactured in a much simpler manner, while having a high filtering efficiency.